GNU Radio嵌入式Python块无法读取参数值的问题求助

我正在给GNU Radio的EmbeddedEmbedded Python Block编写代码，想要实现读取用户点击该块时弹出参数栏里设置的向量长度。但GNU Radio调度器要到流程后期才能获取用户输入的值，导致我的代码始终使用__init__函数里的默认向量长度，影响正常运行。

我试过用相关问题里Djgreene730提供的解决方案，但因为对GRC库和编程知识了解有限（我是电气工程师，非计算机相关专业），没法完成实现和调试。我能确定代码本身没问题，是GRC的机制导致的问题，目前只理解那段代码能找到流图变量的名称，但我需要的是变量的具体值。

我的目标是写一个函数，在流图里找到目标变量并提取它的值，这样就能在__init__函数里覆盖默认值。现在我只能每次修改向量长度时，在代码编辑器里改默认值，操作繁琐。最终想让这个流图对用户友好，不用IDE就能修改参数。

以下是我当前的代码（注：标注为“test code”的部分是Djgreene730提供的代码）：

import numpy as np
from gnuradio import gr
import inspect  # 原代码遗漏该导入，必须添加才能运行

#WindowSize = 1000000

# *** BEGINNING OF TEST CODE ***


def get_top_variable(variable_name="WindowSize", default=None):
    '''
    Returns the value of a variable from the flow graph.
    '''

    # Let's go!
    try:
        ## Run Condition: GNURadio is starting the flowgraph
        top = inspect.currentframe().f_back.f_back.f_locals

        # Check if top has the variable name we're looking for
        if top.__contains__(variable_name):

            # Let the user know we found the variable
            print(f"[Block Debug] While starting, I found top variable '{variable_name}': type={type(top[variable_name])}, value={top[variable_name]}")

            # Return the value of the variable name
            return top[variable_name]

        ## Run Condition: Saving the flowgraph
        top = inspect.currentframe().f_back.f_back.f_back.f_back.f_back.f_locals

        # Make sure top has 'self'
        if top.__contains__("self") and \
                (isinstance(top['self'], grc.gui.canvas.flowgraph.FlowGraph)) and \
                (hasattr(top['self'], 'blocks')):

            # Get a list of all blocks
            block_names = [block.name for block in top['self'].blocks]

            # Find the index to the variable we need
            block_index = block_names.index(variable_name)

            # Store the result
            result = top['self'].blocks[block_index].params['value'].value

            # Let the user know we found the variable
            print(f"[Block Debug] While modifying the flowgraph, I found top variable '{variable_name}': type={type(result)}, value={result}")

            # Return the value of the variable we found
            return result

    # Something went wrong
    except Exception as e:
        print("[Block Debug]: Threw an exception", e)
    except:
        print("[Block Debug]: Threw an unknown exception.")

    # Return the default result
    return default


# *** ENDING OF TEST CODE ***


class blk(gr.sync_block):  # other base classes are basic_block, decim_block, interp_block
    """Embedded Python Block example - a simple multiply const"""

    def __init__(self, window_size = get_top_variable("vlen", default=1)): # = 1  # only default arguments here
        # note on the window_size value: internal, need to get an external variable and sub it in

 #       # *** TEST CODE BEGIN ***
        
        # Get packet length
        vlen = get_top_variable("vlen", default=1)
        print(f"[Block Debug] Setting input length using 'vlen': {vlen}, type={type(vlen)}")
        
 #       # *** TEST CODE END ***


        """arguments to this function show up as parameters in GRC"""
        gr.sync_block.__init__(
            self,
            name='Modulation Monitor',   # will show up in GRC
            in_sig=[(np.complex64, window_size)],
            out_sig=[(np.complex64, window_size)] 

        )
        # if an attribute with the same name as a parameter is found,
        # a callback is registered (properties work, too).

（已省略work()代码，该部分无问题）

内容的提问来源于stack exchange，提问作者Bogus Man